The invention relates to a method of automatically milking animals, such as cows, by robotic means wherein the animals enter the milking parlor to be milked based on their own volition. The invention further relates to a method for controlling spontaneously for each animal the intervals between successive milkings.
Methods for controlling when animals will be accepted in a milking parlor for milking are generally known. When, in the course of such a method, an animal wishes to visit the milking parlor, it is decided on the basis of an admittance criterion (for admitting the animal to the milking parlor) or a milking criterion (for connecting the teat cups of the milking robot to the animal""s udder) or both whether or not the animal should be milked. When either criterion is not met, the animal is not admitted to the milking parlor or is removed therefrom as appropriate.
European Patent EP-A-0 091 892 discloses a system in which a cow is only milked in the milking parlor after a previously determined period of time has elapsed since her last milking. From the International Patent WO-A-95/35028 it is known to use as a milking criterion the number of milkings of other animals since the previous milking of the relevant animal; the animal is only milked when this number at least equals a specific minimum number which may vary from animal to animal. When the milking criterion is not met, the animal is caused to depart from the milking parlor. In other known systems each animal is checked at the entrance of the milking parlor to determine whether or not it was milked at a too recent point of time. The animal is then only admitted to the milking parlor when the applicable admittance criterion has been met.
The above methods have various disadvantages. Animals that, for any reason whatsoever, may wish to visit the milking parlor too often, but thereafter are not admitted to the milking parlor or are quickly caused to leave the milking parlor, may become frustrated. Moreover, when applying each criterion, not only is an animal identification system necessary, but also a system of recording data relevant to the criterion (such as, for example, for each animal the point of time at which the last milking took place) is required.
An object of the invention is to provide an improved method which will result in the animals being milked at appropriate intervals. According to the invention, this is achieved by processing each animal that enters a milking parlor in the same manner as usual which usually includes the cleaning and massaging of the animal""s udder and teats followed by connecting the teat cups to the animal""s teats. However, when a flow meter indicates that the animal has been milked recently, the process thereof is intentionally made disagreeable by actions such as continuing the milking longer than usual or altering the vacuum level at the animal""s teat. This is balanced by making the milking parlor otherwise an attractive place for the animal to visit by a number of means such as dispensing food and drink therein. But the unpleasantness of the milking process when the animals attempt to visit the milking parlor too often soon trains the animal to visit the milking parlor only when it is ready to be milked.